334 Correspondence—Mr. S. V. Wood. 
think that its correlative overstep will be likely to meet with favour, 
and its adoption would certainly emphasize the distinction to which 
Mr. Goodchild has called attention. 
It must be remembered, however, that both cases involve an un- 
conformity, and that the difference between them is really this: 
in overlap the basement member of the upper series has a limited 
extension, while in overstep the basement bed has a continuous 
extension. It is also worthy of remark that the unconformity 
between the two series will generally be much greater in the case 
of overlap than in the case of overstep, for in the latter the beds all 
dip in the same direction, and the existence of an unconformity is 
usually only made patent by the fact of overstep. The real want 
of the term overstep is not in fact brought out by the diagram 
drawn by Mr. Goodchild, since the unconformity there shown is so 
marked that the relation of the upper series to any single member 
of the lower series is not likely to be made a matter of discussion. 
It is only where both series dip evenly in the same direction that 
a term is required to express the relation of the upper to the 
members of the lower series. 
May 18th, 1883. A. J. Jukes Browne. 
CHALK-MASSES IN THE CROMER DRIFT. 
Sir,—Mr. T. M. Reade is mistaken in supposing that I am alone 
in regarding all the larger masses in the “ Cromer Drift” as recon- 
structed Chalk. Jn reference to this, and to his enquiry whether the 
Old Hythe pinnacle of Chalk figured by Sir Charles Lyell was of 
this reconstructed character, I refer him (and others) to page 100 of 
the GrotocicaL Macazine for 1864, where, in a footnote, Prof. H. 
G. Seeley observes as follows :—“ The figures given in Sir C. Lyell’s 
Elements, p. 129, are not included pinnacles of Chalk, but only 
reconstructed chalky drift full of all sorts of rocks.” 
It was the perusal of this note which first called my attention to 
the subject, and Mr. Harmer and I found Mr. Seeley’s statement as 
to the masses being of reconstructed material correct, examining as 
we did the numerous masses worked for marl-pits and lime-kilns 
over the country inland occupied by the Contorted Drift, though in 
most of them fragments of material foreign to the Chalk, save galls 
of sand and clay, and were not common. The sheets interstratified 
in the lower part of the Cromer cliff section, such as that near 150 
yards long at Runton (where this part, heretofore called the Till, is 
represented in Mr. C. Reid’s memoir as the “ Contorted Drift’), are 
of Chalk not reconstructed, and were brought from Chalk shores, 
and dropped on the bottom, as I have pointed out; and, as the sub- 
mergence had then only begun, may very likely have come from 
some part of Norfolk, but when the masses of reconstructed Chall 
were brought, and sunk deep into the substance of the sea-bed, the 
whole of this county was submerged, the highest points in it being 
formed of this sea-bed. For many years before Mr. T. M. Reade’s 
paper on this subject, I have repeatedly referred the transport and 
introduction of these masses to floating ice grounding on the sea- 
